Poly(aryl ether ketones) are known materials which display exceptional high temperature performance. They are crystalline polymers with melting points above 300.degree. C. Two of these crystalline poly(aryl ether ketones) are commercially available and are of the following structure: ##STR1##
Over the years, there has been developed a substantial body of patent and other literature directed to formation and properties of poly(aryl ethers) (hereinafter called "PAE"). Some of the earliest work, such as by Bonner, U.S. Pat. No. 3,065,205, involves the electrophilic aromatic substitution (e.g., Friedel-Crafts catalyzed) reaction of aromatic diacylhalides with unsubstituted aromatic compounds such as diphenyl ether. The evolution of this class to a much broader range of PAE's was achieved by Johnson et al., Journal of Polymer Science, A-1, Vol. 5, 1967, pp. 2415-2427; Johnson et al., U.S. Pat. Nos. 4,107,837 and 4,175,175. Johnson et al. show that a very broad range of PAE can be formed by the nucleophilic aromatic substitution (condensation) reaction of an activated aromatic dihalide and an aromatic diol. By this method, Johnson et al. created a host of new PAE's including a broad class of poly(aryl ether ketones), hereinafter called "PAEK's".
In recent years, there has developed a growing interest in PAEK's as evidenced by Dahl, U.S. Pat. No. 3,953,400; Dahl et al., U.S. Pat. No. 3,956,240; Dahl, U.S. Pat. No. 4,247,682; Rose et al., U.S. Pat. No. 4,320,224; Maresca, U.S. Pat. No. 4,339,568; Atwood et al., Polymer, 1981, Vol. 22, August, pp. 1096-1103; Blundell et al., Polymer 1983, Vol. 24, August, pp. 953-958; Atwood et al., Polymer Preprints, 20, No. 1, April 1979, pp. 191-194; and Rueda et al., Polymer Communications, 1983, Vol. 24, September, pp. 258-260. In early to mid-1970, Raychem Corporation commercially introduced a PAEK called Stilan, a polymer whose acronym is PEK, each ether and keto group being separated by 1,4-phenylene units. In 1978, Imperial Chemical Industries PLC (ICI) commercialized a PAEK under the trademark Victrex PEEK. As PAEK is the acronym of poly(aryl ether ketone), PEEK is the acronym of poly(ether ether ketone) in which the 1,4 -phenylene units in the structure are assumed.
Thus, PAEK's are well known; they can be synthesized from a variety of starting materials; and they can be made with different melting temperatures and molecular weights. The PAEK's are crystalline, and as shown by the Dahl and Dahl et al. patents, supra, at sufficiently high molecular weights they can be tough, i.e., they exhibit high values (&gt;50 ft-lbs/in.sup.2) in the tensile impact test (ASTM D-1822). They have potential for a wide variety of uses, but because of the significant cost to manufacture them, they are expensive polymers. Their favorable properties class them in the upper bracket of engineering polymers.
PAEK's may be produced by the Friedel-Crafts catalyzed reaction of aromatic diacylhalides with unsubstituted aromatic compounds such as diphenyl ether as described in, for example, U.S. Pat. No. 3,065,205. These processes are generally inexpensive processes; however, the polymers produced by these processes have been stated by Dahl et al., supra, to be brittle and thermally unstable. The Dahl patents, supra, allegedly depict more expensive processes for making superior PAEK's by Friedel-Crafts catalysis. In contrast, PAEK's such as PEEK made by nucleophilic aromatic substitution reactions are produced from expensive starting fluoro monomers, and thus would be classed as expensive polymers.
Those poly(aryl ether ketones) exhibit an excellent combination of properties; i.e., thermal and hydrolytic stability, high strength and toughness, wear and abrasion resistance and solvent resistance. Thus, articles molded from poly(aryl ether ketones) have utility where high performance is required. Often, however, in such articles it is important that the crystallinity of the polymer be developed as far as possible during the fabrication process. This is due to the fact that subsequent use of an article which can continue to crystallize in use can result in dimensional changes occuring in the article with consequent warping or cracking and general change in physical properties. Moreover, in some applications, it is important to achieve a uniformity of crystalline texture and to maximize the number of crystallites regardless of increasing the rate of crystallization.
Crystallization rates are even more critical in miscible blends containing a poly(aryl ether ketone) and an amorphous polymer, such as for example, a poly(ether imide) or certain polyimides and poly(amide-imides). The presence of the second polymer component retards crystallization and, hence, the development of optimum toughness, optimum chemical, and heat resistance.
It is, therefore, highly desirable to develop new rapidly crystallizing poly(aryl ether ketone) compositions, while retaining at the same time all of the other attractive features of this class of polymers.
European Patent Application 152,161 describes poly(aryl ether ketones) having high crystallization rates. This is achieved by providing the polymer with ionic end-groups. In another embodiment, fast crystallization is achieved by blending a poly(aryl ether ketone) which does not contain terminal ionic groups with a material having such terminal groups.
U.S. Pat. No. 4,609,714 claims blends of 5 to 95 percent by weight of one poly(aryl ether ketone) with 95 to 5 percent by weight of a second poly(aryl ether ketone). While the patent recognizes that the addition of a higher melting poly(aryl ether ketone) could improve the crystallization kinetics of a lower melting poly(aryl ether ketone), the possibility of using less than 5 percent by weight of the additive to produce fast crystallization was not recognized.